An attack that killed 25 people, mostly students, at a Nigerian school Monday night appeared to be "an inside job" in which the gunmen called out the names of their targets, a police spokesman told CNN Tuesday.

"The attackers went to the houses of the victims, called them out by their names and killed them," Adamawa State Police spokesman Mohammed Ibrahim said. "They used guns and knives on the victims."

Some of the victims' throats were slit, he said.

The armed men attacked a student facility at the Federal Polytechnic, a university in Mubi, Nigeria, Nigeria's National Emergency Management Agency spokesman Yuhau Shuaib said.

Among the 25 killed were 19 Federal Polytechnic students and three students from the School of Health and Technology, Ibrahim said. The three others killed were a school official, a former military man and an older gentleman, he said.

Investigators are trying to determine if the attack was related to upcoming campus elections, he said. "We believe this was an inside job."

"By God's grace, in the next few days we will have some suspects," he said